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Topic: need an electrician (Read 721 times)

i just had a well drilled and i’m doing all of the work installing the water system. the only part i’m unsure of is the wire size i need to the sub panel for the water system. the well pad is 200’ from the housethe submersible pump will be a 240v three wire 1hp pumpthe booster pump will be a 2hp pumpadditionally, i will add in an outlet or two with a light once i build a pump house over the padany help is appreciated

So without know the actual listed amps on the pumps we can make a rough guess.1hp would roughly be 7 amps at 240 volts.2 hp would be roughly 14 amps at 240 volts.So both would likely have a label on them to use a dedicated 20 amp circuit.That does not mean you need 40 amps.....But I would install a 50 amp sub panel so you have a little extra buffer.Normally that would require 6 gauge wire if using copper.But since your over 100 feet your going to need to up the wire size. So #4 for copper and I think #2 if you use aluminum. (I don't have my guide handy.)There is voltage loss on any wire but that should keep you within 3% if I remember correctly.I would run PVC, it will need to be buried at least 18" for normal conditions. Size is going to depend on what wire you choose. Go a little bigger than the minimum.Also check out how you can run it. Conduit can not have more than 360 degrees worth of bends between access points.Slight curves in the ditch that the pipe can take without actually bending it does not count towards the 360.You need 4 wires in the pipe. 2 hots, 1 neutral, and a ground. The ground can be smaller than the other 3. It's an out building so the panel needs to have a main breaker and you will need another ground rod out there. There also may be a requirement to ground the well casing. Ask the well guy he may know.

There could be some stricter codes depending on where you live. Or they may be none.

thank you, this helps a lot i all ready have a 100 amp sub panel, so i’m good there. as far as the conduit, it’s a straight run with a 90° at each end. no, the casing doesn’t require grounding, it’s only steel down 3’ and the rest is pvc.

Don't use aluminum wire, you'll regret it.You said well was 200' from the house. Don't forget to add the well depth to your calculation and distance wire will run inside the house, ie total wire run length.There are a multitude of wire size/voltage drop calculators on the internet and I've seen charts posted in box store like Menards as well. If in doubt, use the larger wire size.